Stainless Steel Coil Tube (盘管) — Online Induction Heating Technology Series
Product Overview
The Stainless Steel Coil Tube (Coiltube, 盘管) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. represents a next-generation tubular product engineered for high-efficiency thermal exchange, chemical processing, and industrial fluid conveyance applications. Distinguished by its innovative integration of Online Induction Heating Technology (在线感应加热技术), this product line achieves superior dimensional stability, enhanced metallurgical properties, and significantly reduced energy consumption compared to conventional coil tube manufacturing methods.
Unlike traditional hot-rolled coil tubes that rely on furnace-based reheating, this product utilizes electromagnetic induction heating directly during the forming process, enabling precise temperature control at the material interface. This technology was originally pioneered for copper coil tubes and has now been successfully adapted and optimized for stainless steel grades, marking a significant advancement in tubular manufacturing technology.
Material & Properties
Available Material Grades
- AISI 304 / 1.4301 — General-purpose austenitic stainless steel with excellent corrosion resistance and formability
- AISI 316L / 1.4404 — Low-carbon austenitic grade with superior resistance to pitting and crevice corrosion
- AISI 321 / 1.4541 — Stabilized austenitic grade for elevated temperature service
- AISI 310S / 1.4845 — High-temperature austenitic grade for extreme thermal environments
- Custom Alloy Grades — Available upon specification for specialized applications
Mechanical Properties (Typical Values)
- Tensile Strength (抗拉强度): ≥ 520 MPa (AISI 304), ≥ 550 MPa (AISI 316L)
- Yield Strength (屈服强度): ≥ 205 MPa (AISI 304), ≥ 220 MPa (AISI 316L)
- Elongation (伸长率): ≥ 40% (AISI 304), ≥ 35% (AISI 316L)
- Hardness (硬度): ≤ 200 HB (annealed condition)
Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Outer Diameter (OD) | Φ6 – Φ219 | mm |
| Wall Thickness | 0.5 – 12.0 | mm |
| Coil Length (per coil) | 50 – 500 (customizable) | m |
| Coil Weight | Up to 5,000 | kg |
| Surface Finish | No.1 / 2B / BA / Mirror / Pickled & Polished | — |
| Heat Treatment Condition | Annealed / Solution Treated / Stress Relieved | — |
| Temperature Control (Induction Heating) | ± 15°C precision | °C |
| Heating Rate | Up to 500°C/min | °C/min |
| Dimensional Tolerance (OD) | ± 0.10 mm (precision grade) | mm |
| Dimensional Tolerance (Wall) | ± 10% (standard), ± 5% (precision) | % |
| Coiling Diameter | 300 – 800 | mm |
| Maximum Working Temperature | Up to 1150°C (grade-dependent) | °C |
Manufacturing Process
Process Flow Diagram
- Raw Material Inspection — Incoming stainless steel strip/coil undergoes spectroscopic analysis (OES), visual inspection, and mechanical property verification to ensure compliance with specified grade requirements.
- Edge Preparation & Cleaning — Strip edges are trimmed and cleaned to remove scale, oxidation, and surface contaminants that could compromise weld integrity.
- Coil Forming (盘管成型) — The flat strip is formed into a tubular cross-section using precision roll forming equipment with synchronized feeding mechanisms.
- Online Induction Heating (在线感应加热) — This is the core differentiating technology. High-frequency electromagnetic coils (typically 10–100 kHz) generate a concentrated thermal field directly at the tube surface, achieving:
- Rapid, uniform heating without thermal lag
- Minimal oxidation scale formation compared to furnace heating
- Precise temperature control for optimal weld metallurgy
- Significant energy savings (up to 40% reduction vs. furnace methods)
- Continuous, high-speed production without batch interruptions
- Welding & Seaming — The heated tube is welded using Automatic Submerged Arc Welding (SAW) or TIG welding processes, with the induction-heated zone ensuring optimal weld pool fluidity and penetration.
- Post-Weld Heat Treatment — Solution annealing (固溶处理) at 1050–1100°C followed by controlled cooling to restore full austenitic microstructure and maximum corrosion resistance.
- Pickling & Passivation (酸洗钝化) — Removal of residual oxide scale through controlled acid immersion, followed by passivation treatment to establish a protective chromium oxide film.
- Coiling & Packaging — The finished tube is coiled onto a steel core with protective wrapping, moisture barrier packaging, and secure strapping for transportation.
Advantages of Online Induction Heating Technology
The adoption of online induction heating technology for stainless steel coil tube production represents a paradigm shift from traditional batch furnace reheating methods. Key advantages include:
- Energy Efficiency — Direct dielectric and eddy current heating achieves thermal efficiency of 60–70%, compared to 20–30% for conventional furnace systems.
- Reduced Scale Formation — Shorter exposure to high temperatures minimizes oxidation, resulting in cleaner tube surfaces and reduced pickling requirements.
- Production Flexibility — Rapid temperature adjustment enables quick changeover between different grades and specifications without extended furnace purging cycles.
- Environmental Benefits — Lower fuel consumption translates to reduced CO₂ emissions, supporting sustainable manufacturing goals.
- Product Quality — Uniform, localized heating produces more consistent weld quality and dimensional accuracy throughout the coil length.
Applications
Primary Industries
- Chemical Processing (化学加工) — Reactor cooling coils, heat exchanger tubes, distillation column internals, and process piping systems handling aggressive media.
- Petrochemical & Oil/Gas (石油化工) — Steam generator tubes, fire-tube boilers, heat recovery units, and offshore platform piping systems.
- Pharmaceutical Industry (制药行业) — Sanitary process coils, CIP (Clean-in-Place) systems, and sterile fluid transfer lines requiring hygienic surface finishes.
- Food & Beverage Processing (食品饮料) — Pasteurization coils, UHT (Ultra-High Temperature) processing tubes, and sanitary heat exchangers.
- Power Generation (电力发电) — Boiler economizer tubes, superheater coils, condenser tubes, and nuclear-grade heat transfer components.
- Marine & Offshore (海洋工程) — Seawater cooling coils, desalination plant heat exchangers, and shipboard piping systems.
- Automotive Industry (汽车工业) — Radiator cores, intercooler tubes, and exhaust system heat management components.
- Heat Exchanger Manufacturing (换热器制造) — Precision coil tubes for shell-and-tube heat exchangers, plate-fin coils, and air-cooled heat exchangers.
Application-Specific Advantages
- The coiled form factor enables continuous processing, reducing fabrication time and material waste by up to 15% compared to straight-length tube cutting operations.
- Consistent weld quality along the entire coil length ensures reliable performance in critical heat transfer applications where weld defects could lead to catastrophic failure.
- The reduced surface oxidation from induction heating produces tubes requiring less post-processing, lowering overall manufacturing costs.
Quality Certifications & Standards
Compliant Standards
- ASTM A213 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for High-Temperature Service
- ASTM A269 — Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Application
- ASTM A313 — Standard Specification for Ferritic Stainless Steel Seamless, Welded, and Heavy-Walled Tubing for High-temperature Service
- EN 10216-5 — Heat Exchanger and Refractory Tubes — Part 5: Non-ferrous metal tubes
- JIS G 4802 — Stainless Steel Tubes for Heat Exchangers
- GB/T 12771 — Stainless Steel Tubes for Fluid Transport (Chinese National Standard)
- GB/T 13296 — Stainless Steel Tubes for Heat Exchangers and Boiler Tubes
- ASME SA-213 / SA-269 — American Society of Mechanical Engineers pressure vessel standards
Certification Body Approvals
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- TÜV — Technical supervision and product certification (where applicable)
- CE Marking — European Conformity for pressure equipment (PED 2014/68/EU)
Quality Control Procedures
- Hydrostatic Testing — 100% pressure testing at 1.5× working pressure to verify weld integrity and structural soundness.
- Eddy Current Testing (ECT) — Non-destructive testing for surface and subsurface defect detection along the full coil length.
- Visual Inspection — Automated optical inspection systems verify surface quality, weld bead uniformity, and dimensional conformity.
- Spectroscopic Analysis — Chemical composition verification via Optical Emission Spectroscopy (OES) for each heat/batch.
- Dimensional Measurement — Laser-based OD and wall thickness gauging with continuous data logging throughout production.
- Mechanical Testing — Tensile, bend, and impact tests performed per ASTM E8/E8M and ASTM E10 standards.
Unique Selling Points
- Pioneering Induction Heating Application — Wenzhou Jixing Metal Materials Co., Ltd. has successfully transferred proven copper coil tube induction heating technology to stainless steel applications, achieving industry-leading production efficiency.
- Superior Surface Quality — The reduced oxidation from induction heating results in cleaner, more uniform tube surfaces ideal for hygienic and high-performance applications.
- Customization Capability — Full customization of dimensions, grades, surface finishes, and coiling configurations to meet specific project requirements.
- Cost-Effective Solution — Energy savings of 30–40% translate to competitive pricing while maintaining premium product quality.
- Environmental Leadership — Lower carbon footprint per ton of finished product, supporting customers' sustainability and ESG goals.
- Technical Expertise — Deep understanding of induction heating metallurgy ensures optimal heat treatment parameters for each stainless steel grade, maximizing mechanical and corrosion performance.
Technical Support & Consultation
Wenzhou Jixing Metal Materials Co., Ltd. provides comprehensive technical support including:
- Material selection guidance based on application parameters (temperature, pressure, medium, environment)
- Custom engineering solutions for specialized coil tube configurations
- Technical documentation including mill test certificates (MTC), EN 10204 3.1 certificates, and traceability records
- On-site technical consultation for heat exchanger design and coil tube integration
- Warranty and after-sales technical support
This product embodies the convergence of traditional metallurgical expertise and modern electromagnetic heating technology, delivering stainless steel coil tubes that meet the most demanding specifications in industrial heat transfer and process engineering.